1. Field of the Invention
The present invention pertains to animal feed compositions which prevent hairball formation and function to reduce the odor of the animal's excrement. Generally the compositions comprise respective amounts of protein, carbohydrate and fat, and are intended to constitute the primary diet for the animal. The compositions also comprise one or more ingredients which bear an electrostatic charge.
2. Description of the Prior Art
Hairball formation is a common physiological problem affecting animals which spend significant amounts of time grooming themselves, consequently ingesting their own hair. Cats are especially susceptible to hairball formation given that self-grooming occupies nearly one-third of their waking hours. Hair which is ingested and does not immediately pass through the cat's digestive track may accumulate in the stomach. After eating a meal and drinking a small portion of water, it is common for the cat to lay down and sleep. These factors taken together create ideal conditions for hairball formation. The hair, food particles, mineral salts, and the cat's own digestive mucus entangle to form a hairball. Hairball formation often leads to vomiting and diarrhea in the animal.
A number of pet food products are available which are directed toward alleviating this problem in animals, especially cats. Fiber-based products utilize cellulose, particularly from wood fiber or beet pulp, as functional ingredients to assist in removal of accumulated hair in the animal's stomach. Oil-based products use mineral oils as lubricating agents for removal of hair from inside the animal's stomach. However, cellulose and mineral oil are not natural components in the diet of cats and can decrease the product's palatability. In order to increase the palatability of these products, flavor enhancers are often added to the products thereby increasing the food's production cost. Fiber and oil-based products also disadvantageously increase the passage of food materials through the animal's digestive tract thereby reducing nutrient digestion and absorption.
U.S. Pat. No. 6,080,403 discloses another proposed method of preventing animal hairball formation. The '403 patent describes a pet food product including the enzyme bromelain, commonly found in pineapple juice. However, bromelain is not suitable for use in moist or canned pet food products due to its instability at temperatures which exceed 170° C.
Therefore, there is a real and unfulfilled need in the art for a pet food composition for preventing hairball formation which comprises a functional ingredient which is a natural part of the animal's diet and which does not detract from the food's nutritional value by interfering with the absorption and digestion of the food product. Furthermore, the functional ingredient should be capable of use in all types of animal feeds regardless of feed moisture content.